Draw punch



April 15, 1930. J. c. NISCHAN 1,754,568

DRAW PUNCH Fil ed Sept. 12, 1927 INVENTOR C A/ASCH/J/V BY 4 9756 ATTORNEY Patented Apr. 15, 1930 UNITED STATES PATENT OFFICE JOHN CHRIS NISCHAN, 0F EVANSTON, II LLINOIS DRAW PUNCH My invention relates to improvements in draw punches, and it consists in the combinations, constructions, and arrangements herein described and claimed.

5 An object of my invention is to provide a draw punch by means of which holes may be cut into sheet metal of any thickness, and which requires only the work of one operator.

A further object of my invention is to provide a device of the type described which is especially adapted for electrical work for cutting holes in metal boxes. The usual method of cutting holes in these boxes is by one operator holding a heavy piece of metal, such as ahammer, against one side of the box and another operator chiseling out the desired opening.

A further object of my invention is to provide a device of the type described by means of which openings may be cut in places where little room is available.

A further object of my invention is to provide a device of the type described which is simple in construction, durable and efiicient for the purpose intended.

Other objects and advantages will appear in the following specification, and the novel features of the invention will be particularly pointed out in the appended claims.

I My invention is illustrated in the accompanying drawings, forming part of this application, in which Figure 1 is a side elevation of the device in the act of cutting a hole in a piece of metal, portions thereof being shown in section.

Figure 2 is a longitudinal section through the punch member, and

Figure 3 is an end elevation of the punch member.

In carrying out my invention, I provide a punch or shearing member 1 having an angular cutaway portion 2 forming shearing edges 3. The punch 1 is provided with a reduced portion 4.- having flattened portions 5 for receiving a wrench or being adapted to be placed in a vise if so desired. The punch 1 is provided with a longitudinally extending threaded opening 6. A recess 7 is provided at the inner extremity of the threaded opening 6.

A die 8 is provided with a relatively large opening 9 arranged to receive the punch 1. The die is also provided with a relatively small opening 10 which is arranged to re ceive a drawbar or punch-moving means 11. The drawbar 11 is provided with a threaded portion 12 arranged to be received in the threaded opening 6 of the punch 1. A shoulder 13 .is integral with the drawbar 11 and is provided with a square head 14 for receiving a ratchet wrench, not shown. A thrust bearing 15 is disposed concentric with the drawbar 11 between the shoulder 13 and the die 8.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood. This device is especially adapted to be used by electricians for cutting larger holes in metal boxes where smaller holes are provided. Let us assume that the strip of metal indicated at 16 is of a box provided with an opening 17 which is not suficiently large for the purpose required by the operator. It may be understood that the size of the die and punch may vary to suit the will of the operator.

To make a larger opening where the smaller opening 17 is shown, the operator may place the drawbar 11 through the opening 17 until the die 8 is in engagement with the strip 16 or portion of the box. The punch 1 is then rotated upon the threaded end of the drawbar 11 until it is in engagement with the member 16. By placing any suitable wrench, preferably a ratchet wrench, upon the head portion 14;, the drawbantogether with the shoulder 13. may be rotated in a clockwise direction. The thrustbearing 15' eliminates the frictional contact between the movable shoulder 13 and the stationary die 8. Movement of the drawbar 11 will cause the punch 1 to move inwardly toward the opening 9 of the die 8. During this inward movement of the punch 1, it is obvious that the shearing edge 3 will engage with the member 16 at opposite points. Continued rotation of the drawbar 11 will cause the punch 1 to move inwardly until the entire shearing edge 3 has passed through the member 16. The punch l is held against rotation by its shearin enagement with the box or strip 16. fter t e shearing edge 3 has passed through the strip 16, the larger opening has been cut therein, and the device may be at once removed.

7 The drawbar 11 is smaller in diameter than the opening 17 and the portion of metal which has been cut from the box may be readily removed from the drawbar.

I claim:

1. A device of the type described comprising a punch, a die arranged to receive said unch, a drawbar rotatabl carried by said die and having a threade end, said punch havin a threaded opening arranged to receive the threaded end of said drawbar, means carried by said drawbar whereby said drawbar may be rotated for moving said punch within said die, and means disposed between said drawbar and said die for aiding in the rotation of said drawbar.

2. A device of the type described comprising a punch having a shearin edge, a die arranged to receive said punc a drawbar having a threaded end receivable in a threaded opening in said punch, a shoulder integral with said drawbar, a bearin disposed between said shoulder and said die, said drawbar being adapted to extend through a relatively small opening in a piece of material, and means carried by said drawbar whereby said drawbar may be rotated formoving said punch within said die for cutting a relatively arge opening in said material.

3. A device of the type described comprising a punch having a t readed opening and transversely extending cutting edges, said cutting edges having diametrically opposed outwardly extending portions and diametrically opposed inwardly extending portions outwards laced at equal distances from sai y extending portions, a die arranged to receive said punch whereb said outwardly extending portions of sai cuttingedges may enter'said die prior to the entering of said' inwardly extending portions, and means for moving said punch into said die.

4. A device of the ty e described comprisa ing a punch having a t readed opening and transversely extendin cutting edges, said cutting edges having fiiametrically opposed outwardly extending portions and diametrically opposed inwardly extendin portions placed at equal distances from sai outwardly extending portions, a die arranged to receive said punch whereby said outwardly extending portions of said cutting edges may enter said die prior to the entering of said inwardly extending portions, and means for moving said punch into said die, said means comprising a drawbar rotatably carried by said die and having a threaded end receivable in the threaded opening in said punch whereby the rotation of said drawbar may cause said punch to move upon said threaded portion.

5. A device of the ty e described comprising a cylindrical punch having an opening and transversely extending cutting edges, said edges having diametrically opposed outwardly extending portions and diametrically opposed inwardly extending portions placed at equal distances from said outwardly extending portions, a cylindrical die arranged to receive said punch whereby said outwardly extending portions of said cutting edges may enter said die prior to the entering of said inwardly extending portions, and means extending through the die and the opening in the punch for axially moving the punch into said die to effect a shearing of material disposed between the punch and die.

JOHN CHRIS NISCl-IAN. 

